1. Field of the Invention
This invention relates to a new and improved flexible plastic tamper-resistant closure for containers of the type in which the bottom of the cap skirt is torn off before the container may be opened. The invention is characterized by the formation on the exterior of the skirt of a flange intended to assist in removing the cap after the bottom of the skirt has been torn away, which flange is located spaced downwardly from the top of the cap and preferably at a level immediately above the circumferential groove formed in the cap to assist in tearing the skirt.
2. Description of Related Art
Caps having skirts formed with internal beads to mate with grooves in container necks are illustrated in U.S. Pat. No. 3,338,446 and in other patents of the assignee of this application. Such a cap has been formed with a circumferential groove intermediate the beads connected to a groove extending down to the bottom edge of the skirt. Tear tabs positioned adjacent the second mentioned groove are also disclosed in the aforementioned patents. Interrupted beads are shown in such patents as U.S. Pat. No. 4,166,552.
It has been found, however, that users sometimes tear the skirts with such force that instead of the skirt being torn circumferentially around the first mentioned groove, the skirt is torn upwardly to or adjacent the top disk of the cap. Various means have been used in the prior art to prevent such tearing. The present invention provides a novel means to resist such tearing.
After the lower part of the skirt has been torn away, various means have been used to assist the user in removing the upper portion of the cap each time the contents of the container are to be dispensed. The use of a flange around the outside of the skirt is shown in U.S. Pat. No. 3,927,784. Since such a flange may be used by dishonest patrons to pry off the cap without tearing away the bottom of the skirt and hence avoids providing evidence of tampering, flange constructions to defeat such purpose have been used. Thus a flexible flange is shown in U.S. Pat. No. 4,166,552, so that when the patron attempts to pull upward on the flange it flexes and cannot be gripped securely to tamper with the cap. A flange having a downward-inward slanted surface such as shown in U.S. Pat. No. 4,484,687 has been used, the slanted bottom edge preventing the fingernails of the user from digging under the flange and hence defeating attempts to tamper.
Flanges of the foregoing type have been located at the outside of the top of the outer skirt of the cap. In accordance with the present invention, such flanges are at a lower level.